Washington: National Aeronautics and Space Organisation (NASA) has for the first time successfully flown its large remotely-piloted Ikhana aircraft in the public airspace without a safety chase airplane, the US space agency said on Wednesday.

"This historic flight moves US one step closer to normalising unmanned aircraft operations in the airspace used by commercial and private pilots," NASA said in a statement.

Flying these large remotely-piloted aircraft over the US opens the doors to services such as monitoring and fighting forest fires to providing new emergency search and rescue operations, according to NASA. The technology in this aircraft could, at some point, be scaled down for use in other general aviation aircraft, it said.

"This is a huge milestone for our Unmanned Aircraft Systems Integration in the National Airspace System project team," said Ed Waggoner, NASA's Integrated Aviation Systems Program director.

Flights of large craft like Ikhana, have traditionally required a safety chase aircraft to follow the unmanned aircraft as it travels through the same airspace used by commercial aircraft. The US Federal Aviation Administration (FAA) granted NASA special permission to conduct this flight under the authority of a Certificate of Waiver or Authorization on March 30.

The certificate permitted Ikhana's pilot to rely on the latest Detect and Avoid technology, enabling the remote pilot on the ground to see and avoid other aircraft during the flight. The flight took off from Edwards Air Force Base in California and entered controlled airspace almost immediately.

Ikhana flew into the Class-A airspace, where commercial airliners fly, just west of Edwards at an altitude of about 20,000 feet. During the return flight, the pilot began a gentle descent over the city of Tehachapi, California, into Class E airspace - about 10,000 feet -where general aviation pilots fly.

The pilot initiated an approach into Victorville airport at 5,000 feet, coordinating in real time with air traffic controllers at the airport. After successfully executing all of these milestones, the aircraft exited the public airspace and returned to its base at Armstrong.